The invention relates to a heater for installation on the floor or in side walls of a motor vehicle.
A heating system disposed on the floor of a motor vehicle, in which the heater comprises a block of pipes and ribs, as well as lateral header compartments into which the pipes discharge, is known from German Utility Model No. 16 50 455. This heating system was intended as the sole heater for a motor vehicle, and heat exchangers completely of metal and having high heat transfer coefficient were accordingly provided. The surface heat exchangers for the floor of a motor vehicle which are known from this utility model have the disadvantages of a relatively high manufacturing cost and relatively high weight, however, because they are entirely of metal. Furthermore, a cover plate must be provided in order to protect the ribs and prevent soiling of the heat exchanger.
Presently, motor vehicle heating systems are designed completely differently, because the heater is usually located in a heater housing between the dashboard and the firewall, and a flow of air is heated in the heater and introduced into the passenger compartment. In order to attain an effective heating capability, however, these systems require the operation of a blower, which, on the one hand, causes a perceptible draft, and, on the other, produces a considerable amount of noise.
Heating plates for the floor heating system of a motor vehicle are also known from German Offenelgungsschrift No. 19 62 665. These plates are made substantially of rubber, and are interspersed with channels that can be connected to the coolant circulation of the motor vehicle. Heat exchangers of this type have not be successful, however, because on the one hand they lack the necessary strength and rigidity, and on the other hand, the thermal conductivity of the rubber material is inadequate.